JPS6029897A - Fire detection - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a fire detection method for detecting fires.

Fire detection methods include a method of detecting smoke and a method of detecting temperature y1.

The former includes a light source and a light receiver, the light receiver is installed outside the light beam emitted from the light source, and the light receiver receives the scattered light generated when smoke enters the light beam, thereby eliminating smoke. It is designed to detect the occurrence of a fire.

In the latter method, a thermistor, thermoelectromotive force element, or the like is used as the temperature detection element.

By the way, smoke detectors that detect smoke are more sensitive than those that detect temperature, and are more likely to malfunction due to things like grass smoke and dirt.

Those that detect temperature are less sensitive than those that detect smoke. Therefore, it is inappropriate for early detection. In order to solve this problem, it is conceivable to lower the set temperature at which the alarm is issued, but doing so would make malfunctions more likely.

Furthermore, since temperature is detected using an electrical method, it is susceptible to electromagnetic noise, making it unsuitable for places with a lot of electromagnetic induction, such as factories.

The present invention solves the above-mentioned drawbacks and provides a highly reliable fire detection method that is free from malfunctions.

Therefore, the present invention projects the light from the light projection fiber l onto the temperature sensitive body 2 which changes depending on the temperature to block or pass the light,
The light that has passed through the temperature sensing element 2 is projected onto the smoke detection section 3 and scattered by smoke, and the scattered light is received by the light receiving fiber 4 to detect temperature and smoke.

An example of the present invention shown in FIG. 1 transmits light from a light source 5 through a light projection fiber 1, and projects the light onto a temperature sensitive body 2 that changes depending on temperature.

The thermosensitive body 2 has a transparent liquid 8 placed between mercury columns 6 and 7 that are opaque to light, and the mercury columns 6 and 7 change to A as the temperature rises and falls.
When the transparent liquid 8 falls, the light from the light emitting fiber 1 passes through the transparent liquid 8 of the temperature sensor 2 and the mercury columns 6 and 7.
It is designed so that it can be blocked by

When the light from the light emitting fiber 1 passes through the temperature sensing element 2, it is received by the relay fiber 9, which faces the light emitting fiber 1 with the temperature sensing element 2 in between, and is emitted from its output end to the smoke detection unit 3. Ru. The emitted light is scattered by the smoke detection section 3 and received by the light receiving fiber 4. The light from the light receiving fiber 4 is converted into an electrical signal by the optical temperature converter 0/E and detected. This allows temperature and smoke to be detected simultaneously.

The axis of the light receiving fiber 4 is shifted from the relay fiber 9 by 90 degrees so that the light from the relay fiber 9 does not directly enter the fiber.

Another embodiment of the present invention, shown in FIG. 2, uses a combination of a light-shielding plate 11 with an opening in which a passage 10 is formed and a bimetal 12 as the temperature sensor 2.

This is because when the ambient temperature of the bimetal 12 rises to -H due to the occurrence of a fire, etc., the bimetal 12 rises upwards, and as a result, the apertured light shielding plate ti rises and blocks or passes the light from the light emitting fiber l. do.

The relay fiber 9 and the light receiving fiber 4 in FIG. As a result, the scattered light that is projected from the output end of the relay fiber 9 to the smoke detection section 3 and scattered is incident on the input end of the light receiving fiber 4.

The one shown in FIG. 3 uses the same thermosensor 2 as the thermosensor shown in FIG. 1, and a lens 12 is provided in front of the transparent liquid 8.
This lens 12 converts the light from the light emitting fiber 1 into a parallel light beam, and the bundled light receiving fibers 4 are arranged obliquely to the axis of the light beam. Thereby, the parallel light flux that has passed through the transparent liquid 8 and entered the smoke detection section 3 is scattered by the smoke of the smoke detection section 3 and is made to enter the light receiving fiber 4.

The O/E in FIGS. 2 and 3 is an optical-to-electrical converter.

As described above, the present invention projects light from a light projection fiber l onto a temperature sensing element 2 that changes depending on the temperature, blocks or passes the light, and transmits the light that has passed through the temperature sensing element 2 to a smoke detection section 3. This scattered light is received by the receiving fiber 4, and a fire is detected only when both smoke and temperature are detected. It is possible to detect fires with higher accuracy than those that detect fires only from fires.

In addition, the operating temperature of thermosensor 2 is higher than the highest temperature indoors all year round! If you set it to a high value, it will not malfunction even if the outside temperature rises a little. Further, even if smoke occurs at room temperature, the light receiving fiber 4 does not receive light from the light emitting fiber 1, so no signal is input to the light-to-temperature converter 07H, and therefore, the smoke is not detected, so no malfunction occurs.

If a low-loss fiber is used as the optical fiber used in the present invention, long-distance detection can be performed without M guide, so fire monitoring over a wide range can be performed.

[Brief explanation of the drawing]

FIGS. 1 to 3 are explanatory diagrams showing each step of the present invention. (1) is a light emitting fiber (2) is a thermosensor (3) is the smoke detection part (4) is the receiving fiber

Claims (1)

[Scope of Claims] (1) Light from a light projection fiber is projected onto a temperature sensing element that changes depending on the temperature, the light is blocked or passed, and the light that has passed through the temperature sensing element is projected onto a smoke detection section. A fire detection method in which temperature and smoke are detected by scattering the scattered light and receiving the scattered light with a light-receiving fiber (2) As a temperature sensor, a transparent liquid is used between the upper and lower mercury columns (3) The fire detection method (3) according to claim 1, wherein a combination of a light-shielding plate with an opening and a bimetal is used as the temperature sensor.
Fire detection method described in section